Play was halted in the 40th minute and suspended for 20 minutes when fans and players alerted medical staff that a fan had suffered a cardiac arrest in the stands.
The fan received treatment from Newcastle's club doctor, Paul Catterson, before being transferred to hospital.
A statement read: "Newcastle United can confirm that a supporter who required emergency medical treatment during the club's Premier League fixture with Tottenham Hotspur at St James' Park on Sunday is stable and responsive in hospital.
"The match was temporarily suspended during the incident, which occurred during the first half, and the supporter was awake and able to converse upon being transported to hospital.
"The club would like to thank fans for their swift actions in raising the alarm and praise those who provided immediate chest compressions, as well as thanking the on-site medical professionals who swiftly administered emergency treatment using a defibrillator located close to the incident.
"Our best wishes go to the supporter and their loved ones and we hope for a swift and full recovery."
Newcastle went on to lose the game to Spurs 2-3.
